MongoDB C++ Driver legacy-1.0.0 socketTimeout

I could not find documentation on the legacy driver 1.0.0 where they define what socketTimeout = 0 indicates. I would expect that to mean no timeout, but wanted to confirm and would appreciate if someone can answer what the default value of socketTimeout = 0 indicates?

ref : line 248 ( DBClientBase* connect( std::string& errmsg, double socketTimeout = 0 ) const;) from